Texas A&M quarterback Johnny Manziel continues to practice with the Aggies team as the NCAA investigates allegations he was paid for signing his autograph. / Troy Taormina, USA TODAY Sports

by George Schroeder, USA TODAY Sports

by George Schroeder, USA TODAY Sports

Last week, the troubled football star's mother answered the door at her home in a golf course development just south of the Texas A&M campus. Even before opening the door, she was already waving away a reporter.

"We're not talking," Michelle Manziel said. She apologized, and then closed the door again.

There wasn't much she or anyone else connected with Johnny Manziel could have said. Not long after news had broken of allegations the Heisman Trophy winner had accepted money for signing his autograph on piles of memorabilia, there was little certain about his status, other than this: Manziel was practicing with the Aggies. The NCAA was investigating. And kickoff was coming in a hurry.

The biggest question is whether the reigning Heisman Trophy winner will be under center Aug. 31 when Texas A&M opens the season at home against Rice â?? or under center at all this season.

Since the allegations first surfaced there have been more allegations by autograph dealers. Texas A&M hired a high-powered law firm with experience in NCAA investigations. The Manziel family hired an attorney with experience in NCAA investigations. The NCAA, which declines to discuss pending or current investigations, is investigating.

As kickoff edges closer, those who say they know what's going to happen with Johnny Football, well, doesn't. That's one reason the people involved aren't saying much at all: From here, the story could spin off in several directions.

Now, roughly two weeks since the allegations emerged and two weeks from kickoff, USA TODAY Sports college football reporter George Schroeder examines the alleged violation, how history may inform the investigation, and how Manziel, Texas A&M and NCAA might proceed.

THE INVESTIGATION

The NCAA is digging, and Texas A&M is conducting its own investigation. What might have turned up isn't certain. Several autograph dealers allege Manziel accepted thousands of dollars for signing thousands of autographs. NCAA Bylaw 12.5.2.1 prohibits student-athletes from accepting money for promotion or sale of a product or service.

In news reports, there is rich detail and seemingly damning circumstantial evidence. For example, in a video that ESPN reported having seen (but which has not been made public), Manziel allegedly said, "you never did a signing with me." That same autograph dealer said he paid Manziel $7,500 and that Manziel told him he planned to buy new rims for his car with the money.

But there hasn't been proof of money changing hands.

There's also this detail: The autograph dealers, mostly anonymous, have said they are not talking with the NCAA. That's important. The NCAA cannot use news reports as evidence, but must conduct its own interviews. Also, any allegations must be made on the record â?? from named sources.

Perhaps making it more difficult for the NCAA to persuade autograph dealers to cooperate is a Texas law that makes anyone who "knew or reasonably should have known" he was breaking NCAA rules (or causing someone else to break them) "is liable for damages in an action brought by an institution."

Even if the NCAA persuaded autograph dealers to talk, it might still need a paper trail of payment â?? a check, for example â?? for proof. Although Manziel must turn over bank records to the NCAA, investigators cannot compel others (including, for example, Nathan Fitch, Manziel's friend and "personal assistant," who has been named in some of the allegations) to do the same. Even then, transactions in the autograph memorabilia business are often conducted in cash. In the absence of a paper trail, even evidence of large deposits into Manziel's bank account might not prove much, given his family's financial resources.

It's important to note the NCAA's standard of proof is not "beyond a reasonable doubt," but instead "clear and convincing evidence."

POSSIBLE PENALTIES

If Manziel is found to have broken the rules, he'll almost certainly be declared ineligible. How many games he'd miss before reinstatement might depend on several factors, including the amount of money he would have been found to have accepted. It's always tricky to take past NCAA cases as precedent. Then-Georgia receiver A.J. Green missed four games in 2010 for selling his 2009 Independence Bowl jersey for $1,000. Several Ohio State players were suspended for five games in 2012 for selling memorabilia or for exchanging memorabilia for tattoos.

The allegations of payments by autograph dealers would seem to indicate Manziel received a lot more money than the players in those examples; the first report alone was that a Florida autograph broker named Drew Tieman paid Manziel a "five-figure flat fee" in January. If the NCAA proved all or most of the allegations, Manziel might face a much longer suspension than those other players.

On the other hand, compromise could occur. John Infante, a former university compliance officer and proprietor of The Bylaw Blog, which covers NCAA compliance issues, suggested a scenario â?? though he said he considered it unlikely â?? in which the NCAA offered Manziel limited immunity for telling them how the autograph process worked, the idea being to get a better handle on whether it was a pervasive problem, and a better idea of how to combat it. In that case, Infante envisioned a reduced suspension: conveniently, for example, of two games, which would restore Manziel's eligibility before the Aggies played Alabama Sept. 14 in what's expected to be one of the biggest games of the college football season.

There would be criticism for letting Manziel off lightly. But considering the apparent difficulty of proving the violations, such a solution would allow the NCAA to avoid a situation like it had with Auburn's Cam Newton in 2010 â?? when, Infante said, "Everybody feels he did something wrong but nobody can prove anything, and the rules aren't helping."

"You can say (Manziel) 'admitted to it, he gave us information and helped the larger effort, so we wanted to send the message that we were rewarding him' for helping," Infante said.

The NCAA might not have to prove Manziel took the money to mandate severe punishment. In early October 2009, then-Oklahoma State receiver Dez Bryant was ruled ineligible for lying to the NCAA about visiting the home of former NFL star Deion Sanders. He missed the remainder of the season. If Manziel is found to have misled investigators, he could be penalized for that offense.

Earlier this week, Bryant said he would "be mad" if Manziel escaped suspension. But Bryant also said he's more angry at the NCAA, saying college athletes should be paid and that players should be able to sell their autographs.

"I think what would be OK," Bryant said, "would be to have just a little bit of money in your pocket."

That sentiment, which is increasingly shared by others, is among the external factors that complicate the situation.

PRESSURE POINTS

The investigation isn't happening in a vacuum. Given the high profile of Manziel as the reigning Heisman Trophy winner, and the attention the allegations have received, there's intense pressure for the NCAA to make the case. But there will also be intense scrutiny on whether and how the NCAA does it.

That's in part because of high-profile bungling in the enforcement staff's investigation of Miami. It's because of a sense the NCAA vastly overreached its authority â?? and completely stepped outside its established process â?? in punishing Penn State for wrongdoing in the Jerry Sandusky child sex abuse case.

"It has to be very thorough," said Infante of the investigation, "but it has to be very 'by the book.' "

In addition, as alluded to by Bryant, atmospheric conditions have never been so predisposed toward an athlete and against NCAA policy.

The Ed O'Bannon lawsuit, in which former and current college athletes are suing the NCAA over the use of their names and likenesses, continues to pick up steam in the courts. Last week, TV analyst Jay Bilas discovered the search function on a memorabilia shop linked to the NCAA's own commercial website would yield a Texas A&M jersey with the No. 2 if he input "Manziel," and the same with other current and former stars' names. This prompted the NCAA to hurriedly stop selling team gear on its site, doing serious damage to the idea, as the organization has long argued, that jersey numbers don't represent actual college athletes.

In addition, major college conferences have tried (and failed) to enact legislation to provide players with stipends above their current scholarships; in part because of it, a radical reorganization of the NCAA's governance structure appears on the way, and soon.

Although Manziel might not be an especially sympathetic figure â?? if he took payments, it wasn't to buy, for example, a winter coat â?? the climate might make it difficult for the NCAA to severely punish college football's biggest star.

"The question is," Infante said, "how hard are they willing to hammer him, or how hard are they willing to hold this over A&M's head about playing him?"

Texas A&M faces pressure, too, both to ensure it has done a serious and thorough investigation and, if something turns up, to declare Manziel ineligible (the school would then seek his reinstatement from the NCAA).

Looming over everything is the clock, which is counting down to a 1 p.m. ET kickoff Aug. 31 against Rice. If the investigation drags on, unresolved, Texas A&M must determine the risks of playing Manziel. It's likely the school would seek advice from the NCAA on the best course of action and that if Manziel played, the school would seek assurance it would not be penalized if information came to light later.

One other possibility? If Manziel is suspended, there's always the possibility he could file suit against the NCAA or Texas A&M.

Given all of those factors and more, the standard of proof for the NCAA appears higher than usual, and severe punishment seems perhaps more difficult to sell.

"It fits so neatly," said Infante of a light punishment. "He broke a rule and should be punished, but the rule is unfair and so he shouldn't really be punished. If it was a slap on the wrist where he got punished but then everybody was able to move on, that might be good."

George Schroeder, a national college football reporter for USA TODAY Sports, is on Twitter @GeorgeSchroeder.